SOLUTION: IT takes the same amount of time for a boat on the river to go downstream 15 miles as it does to go upstream 9 miles. If the river current is 5mph what is the speed of the bat in
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Question 360699: IT takes the same amount of time for a boat on the river to go downstream 15 miles as it does to go upstream 9 miles. If the river current is 5mph what is the speed of the bat in still water? Answer by ewatrrr(24785) (Show Source):
Hi,
*Note: d = r*t or t = d/r
IT takes the same amount of time ...
Let r represent speed in still water
cross multiply and solve for r
15(r-5)= 9(r+5)
15r - 75 = 9r + 45
6r = 120
r = 20 mph
checking our answer
15/25 = 9 /15 = 3/5
